Tone map example of Gray-Scott diffusion using toxiclibs in ruby processing

Another rubified example, showing how to use some of the toxiclibs in ruby-processing. Any observations/questions could be made on the processing alternative implementations forum, which I often watch.


#
# <p>GrayScottToneMap shows how to use the ColorGradient & ToneMap classes of the
# colorutils package to create a tone map for rendering the results of
# the Gray-Scott reaction-diffusion.</p>
#
# <p><strong>Usage:</strong><ul>
# <li>click + drag mouse to draw dots used as simulation seed</li>
# <li>press any key to reset</li>
# </ul></p>
#

#
# Copyright (c) 2010 Karsten Schmidt
#
# This demo & library is free software you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation either
# version 2.1 of the License, or (at your option) any later version.
#
# http://creativecommons.org/licenses/LGPL/2.1/
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
#

class GrayScottToneMap < Processing::App
  load_libraries 'simutils','toxiclibscore','colorutils'
  include_package "toxi.sim.grayscott"
  include_package "toxi.math"
  include_package "toxi.color"
 
  NUM_ITERATIONS = 10

  attr_reader :gs, :tone_map

  def setup()
    size(256,256)
    @gs= GrayScott.new width,height, false
    @gs.set_coefficients 0.021, 0.076, 0.12, 0.06
    # create a color gradient for 256 values
    grad = ColorGradient.new
    # NamedColors are preset colors, but any TColor can be added
    # see javadocs for list of names:
    # http://toxiclibs.org/docs/colorutils/toxi/color/NamedColor::html
    # NB: use '::' in place of '.' here for these java constants
    grad.add_color_at(0, NamedColor::BLACK)
    grad.add_color_at(128, NamedColor::RED)
    grad.add_color_at(192, NamedColor::YELLOW)
    grad.add_color_at(255, NamedColor::WHITE)
    # this gradient is used to map simulation values to colors
    # the first 2 parameters define the min/max values of the
    # input range (Gray-Scott produces values in the interval of 0.0 - 0.5)
    # setting the max = 0.33 increases the contrast
    @tone_map = ToneMap.new 0, 0.33, grad
  end
 
  def draw()    
    @gs.set_rect(mouse_x, mouse_y, 20, 20) if mouse_pressed?
    load_pixels
    # update the simulation a few time steps
    NUM_ITERATIONS.times { @gs.update(1) }
    # read out the V result array
    # and use tone map to render colours
    gs.v.length.times do |i|
      pixels[i]=tone_map.getARGBToneFor(gs.v[i])  # NB: don't camel case convert here
    end
    update_pixels
  end
   
  def key_pressed
    @gs.reset()
  end
 
end